For example, US-2003/0120724-A1 discloses a following technique. That is, in response to a processing request from a client A, a load distribution apparatus B inquires operational states of respective servers C, D and E, selects a first server apparatus C as a server that will execute the processing, based on the results, and by connecting the client with the server apparatus and instructing the start of the processing, the first server apparatus C starts the processing. Here, when data necessary for the processing is found, the server apparatus C outputs a data acquiring request to an application layer server F while it records process information necessary for the restart of the processing into a shared storage means G. When, in the application layer serve F, the creation of the data necessary for the processing is completed and a data reply request is output, a system control apparatus H inquires the operational states of the server apparatuses C, D and E after the data is received, and selects a server apparatus that will restart the processing. As this selection method, a server apparatus that will execute the subsequent processing most efficiently is selected, based on a server apparatus whose load is lightest among the server apparatuses C, D and E, a server apparatus whose number of other processings being currently executed is the smallest, or the like. When the selected server apparatus is the third server apparatus E, the processing is restarted in a server different from the server apparatus C, which initially executed the processing. In this case, the system control apparatus H firstly transmits a connection change request to instruct the change from the connection between the client A and the server apparatus C to the connection with the server apparatus E, to a load distribution apparatus B. The load distribution apparatus B carries out the connection change between the client A and the server apparatus, according to this connection change request. After that, the system control apparatus H transfers the data acquired by the application layer server F to the server apparatus E, and transmits the processing restart instruction. The server apparatus E, which received the transferred data and the processing restart request, does not have the process information necessary for the processing restart, because the server apparatus E is different from the server that carried out the processing before the data is acquired. Then, the server apparatus E refers to the process information, which is necessary for the processing restart and is stored in the shared storage means G, to restart the processing. Thus, by carrying out the load distribution also when the data is acquired and the processing is restarted after the processing is temporarily stopped in order to acquire the data, a further efficient operation of Web layer servers is realized.
However, in the aforementioned technique, because the server apparatus that initially carried out the processing in response to the request from the client A should be selected and the server apparatus that sends a response for the same request should be further selected, it is necessary to carry out a server selection processing twice in order to process one request, and when the loads of the server apparatuses are almost uniform, an additional time for one server selection processing is required. In addition, when the load state is inquired to each server apparatus for each server selection processing, additional loads are required. In the aforementioned technique, when a fault occurs in the server apparatus after the processing is requested to the application layer server, it is possible to complete the processing without affecting the client. However, because the fault occurrence affects the client in a case where the fault occurs after the processing firstly started in the server apparatus or while the data from the application layer server is processed, there is no large effect as the fault countermeasure.